An electrical junction box for a vehicle is generally an electrical module including switching elements enabling electric current to be distributed to the various accessories of the vehicle. This junction box is generally denoted using various other terms, such as ‘power distribution box’ or ‘relay box’. This box is generally controlled by an electronic control module including a microcontroller enabling the acquisition of commands from the user of the vehicle.
The electrical junction box of a vehicle is the core for power distribution and circuit protection in the vehicle. The main aim of the electrical junction box is to provide a central location for the electric power and signal distribution for the circuits of vehicles, and their associated electrically controlled components. The electrical junction box includes a power distribution system and a printed circuit board for controlling the assembly of fuses and switching devices, such as relays. The electrical junction box is in electrical communication with a control housing. The control housing is a control unit that processes the commands from the user of the vehicle, and sends signals to the relays contained in the electrical junction box so as to control the windscreen wipers, the car lights, the defrosting system, etc. The control housing and the electrical junction box are typically two separate assemblies that are situated remotely from one another inside the body of the vehicle.
The relays are conventionally controlled by electronic modules via connections that are wired to the control housing. The electrical junction box is generally linked to the control housing via a wiring harness and standard cable connectors, thereby leading to a large number of connectors, connector strips and copper tracks on the printed circuit board.